The effect of level and distribution of concentrate supplementation on performance of first calving dairy cows

Abstract

A total of 119 dairy cows in their first lactation and with a mean calving date of 6 december were used in a 3-year experiment. The experiment was designed to examine the effect of level and distribution of concentrate given during the winter period in addition to grass silage (ad libitum) and hay (4 kg/d) on total lactation performance. Each year the same 5 treatments were compared : 3 levels of concentrate supply during the winter period (high H, medium M and low B), and, for levels M and B, 2 different allocation patterns (« classic » (C) or « uniform » (U)). Concentrate allocation was individually pre-determined according to expected milk production. During summer, all animals grazed together as a single treatment. During the experimental period (weeks 4 to 18 of lactation), concentrate and roughage intakes were 6.3, 4.8 and 3.5 kg DM/d and 9.2, 9.5 and 9.8 kg DM/d in treatment H, M and C respectively. Milk production and protein content of treatment H were higher than treatment MC (+ 1.2 kg/d and + 0.6 g/kg) or BC (+ 3.1 kg/d and + 1.7 g/kg). During winter, liveweight changes were + 1, - 26 and - 39 kg for treatment H, M and B respectively. On total lactation (305 d), milk production and concentrate supply differences were 169 kg and 202 kg DM between treatments H and M, and 577 kg and 420 kg DM between treatments H and B. There was no significative difference between treatments C and U.